使用第二个元素进行分类

Question

从这个数组开始：

$TEST=array (
    0 => array ( 0 => 'b', 1 => 'y', 2 => 'O', ),
    1 => array ( 0 => 'a', 1 => 'z', 2 => 'O', ),
    2 => array ( 0 => 'c', 1 => 'x', 2 => 'O', ),
)

如何排序它有？（基于第二个元素的 xyz）：

$TEST=array (
    2 => array ( 0 => 'c', 1 => 'x', 2 => 'O', ),
    0 => array ( 0 => 'b', 1 => 'y', 2 => 'O', ),
    1 => array ( 0 => 'a', 1 => 'z', 2 => 'O', ),
)

简单 asort($TEST) 的结果是（基于第一个元素的 abc）：

$TEST=array (
    1 => array ( 0 => 'a', 1 => 'z', 2 => 'O', ),
    0 => array ( 0 => 'b', 1 => 'y', 2 => 'O', ),
    2 => array ( 0 => 'c', 1 => 'x', 2 => 'O', ),
)

Answer 1

你可以用这一行代码来做到这一点：

array_multisort( array_column($yourArray, $index), SORT_ASC, $yourArray );

对于您的情况，这是如何使用它的：

$TEST=array (
    0 => array ( 0 => 'b', 1 => 'y', 2 => 'O', ),
    1 => array ( 0 => 'a', 1 => 'z', 2 => 'O', ),
    2 => array ( 0 => 'c', 1 => 'x', 2 => 'O', ),
)
array_multisort( array_column($TEST, 1), SORT_ASC, $TEST );
print_r($TEST);

在此处勾选array_multisorthttp://php.net/manual/en/function.array-multisort.php

Answer 2

带有宇宙飞船的显式 uasort：

<?php

$items = [
    0 => [ 0 => 'b', 1 => 'y', 2 => 'O' ],
    2 => [ 0 => 'c', 1 => 'x', 2 => 'O' ],
    1 => [ 0 => 'a', 1 => 'z', 2 => 'O' ]
];

uasort($items, function($a, $b) { return $a[1] <=> $b[1]; });
var_export($items);

输出：

array (
  2 => 
  array (
    0 => 'c',
    1 => 'x',
    2 => 'O',
  ),
  0 => 
  array (
    0 => 'b',
    1 => 'y',
    2 => 'O',
  ),
  1 => 
  array (
    0 => 'a',
    1 => 'z',
    2 => 'O',
  ),
)

写在短箭头函数符号中：

uasort($items, fn($a, $b) => $a[1] <=> $b[1]);

使用第二个元素进行分类

asort using the second element

php

sorting

asort